24 July 2021 HAYNES®
Haynes 556 Nickel Based Superalloy
HAYNES® 556 alloy (UNS R30556) is an iron-nickel-chromium-cobalt alloy that combines effective resistance to sul dizing, carburizing and chlorine-bearing environments at high temperatures with good oxidation resistance, fabricability, and excellent high-temperature strength. It has also been found to resist corrosion by molten chloride salts and other salts, and is resistant to corrosion from molten zinc.
Chemical Composition:
| C | Mn | Si | P | S | Al | Ta | Nb | La | Zr | N | B | Cr | Ni | Co | Mo | W |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.05 | 0.5 | 0.2 | 0.1 | 0.3 | 0.005 | 0.001 | 0.1 | 21 | 19 | 16 | 2.5 | 2 | ||||
| 0.15 | 2 | 0.8 | 0.04 | 0.015 | 0.5 | 1.25 | 0.3 | 0.1 | 0.1 | 0.3 | 0.02 | 23 | 22.5 | 21 | 4 | 3.5 |
Ease of Fabrication:
HAYNES® 556 alloy has excellent forming and welding characteristics. It may be forged or otherwise hot-worked, providing that it is held at 2150°F (1175°C) for a time suf cient to bring the entire piece to temperature. As a consequence of its good ductility, HAYNES® 556 alloy is also readily formed by cold working. All hot- or cold-worked parts should be annealed and rapidly cooled in order to restore the best balance of properties.
The alloy can be welded by a variety of techniques, including gas tungsten arc (GTAW), gas metal arc (GMAW), shielded metal arc (coated electrode), and resistance welding.
Heat-Treatment:
HAYNES® 556® alloy is furnished in the solution heat-treated condition, unless otherwise speci ed. The alloy is normally solution heat-treated at 2150°F (1175°C) and rapidly cooled or water-quenched for optimum properties. Heat treatments at temperatures lower than the solution heat-treating temperature may cause precipitation of secondary phases.
Applications:
HAYNES® 556 alloy combines properties which make it highly useful for service at elevat- ed-temperature in moderately to severely corrosive environments. Applications can include tubing and structural members in municipal and industrial waste incinerators, rotary calcin- ers and kilns for minerals processing, and non-rotating components in industrial gas tur- bines burning low-grade fuels.
In the chemical process industry, HAYNES® 556 alloy is used for applications in rotary calciners, car- bon regenerators, and in processes involving high-sulfur petroleum feedstocks.
In the metallurgical process industry, HAYNES® 556 alloy is widely used for hot-dip galvanizing x- tures, spinners and baskets, and for high speed furnace fans. HAYNES® 556 alloy is also employed in air preheaters of diesel engines, the inner covers of coil annealing furnaces, and in vari- ous high-temperature applications in the aerospace industry.